Process and apparatus for minimizing the potential for explosions in the direct chill casting of lithium alloys

Abstract

An apparatus and a system including a casting pit; a mold including a reservoir and a cavity; a coolant feed operable to introduce a coolant to a periphery of a metal emerging from the mold cavity; an array of water vapor exhaust ports about at least the top periphery of the casting pit; a mechanism to introduce an inert fluid into the coolant feed. A method for a direct chill casting including, after detecting a bleed out, exhausting generated gas from the casting pit at a flow volume rate that is enhanced relative to a flow volume rate prior to detecting bleed out or run out; introducing an inert gas into the casting pit; and introducing an inert fluid into a coolant feed to the casting mold.

What is claimed is: 
     
       1. A method for a direct chill casting of an aluminum lithium alloy wherein a molten metal is introduced into a casting mold and cooled by the impingement of a coolant on the solidifying metal in a casting pit having top, intermediate and bottom portions and including a movable platen comprising:
 detecting a bleed out or a run out; and 
 after detecting a bleed out or run out:
 exhausting generated gas from the casting pit at a flow volume rate that is enhanced relative to a flow volume rate prior to detecting bleed out or run out; while exhausting generated gas, 
 introducing an inert gas into the casting pit, the inert gas having a density less than a density of air; 
 introducing an inert fluid into a coolant feed associated with the casting mold; and 
 stopping a flow of coolant to the coolant feed. 
 
 
     
     
       2. The method of  claim 1 , wherein the inert fluid comprises a helium gas or a mixture of a helium gas and an argon gas. 
     
     
       3. The method of  claim 1 , wherein exhausting generated gas from the casting pit comprises exhausting by an array of exhaust ports about at least a periphery of a top portion of the casting pit. 
     
     
       4. The method of  claim 3 , wherein exhausting generated gas further comprises exhausting by arrays of exhaust ports about the intermediate and bottom portions of the casting pit. 
     
     
       5. The method of  claim 1 , wherein introducing an inert gas comprises introducing an inert gas through an array of gas introduction ports about a periphery of at least a top portion of the casting pit. 
     
     
       6. The method of  claim 1 , wherein introducing an inert gas comprises introducing an inert gas through arrays of gas introduction ports about a periphery of a top portion, an intermediate portion and a bottom portion of the casting pit. 
     
     
       7. The method of  claim 1 , further comprising, after detecting a bleed out or run out, stopping a flow of molten metal into the casting mold. 
     
     
       8. The method of  claim 1 , wherein the inert fluid is helium gas. 
     
     
       9. The method of  claim 1 , wherein the inert fluid is a mixture of a helium gas and an argon gas. 
     
     
       10. The method of  claim 1 , wherein the inert fluid is a mixture of a helium gas and an argon gas comprising at least about 20% of the helium gas. 
     
     
       11. The method of  claim 1 , wherein the inert fluid is a mixture of a helium gas and an argon gas comprising at least about 60% of the helium gas. 
     
     
       12. The method of  claim 1 , wherein a bleed out or a run out comprises detecting a bleed out or run out of a lithium-aluminum alloy. 
     
     
       13. The method of  claim 12 , wherein the lithium aluminum alloy comprises about 0.1 percent to six percent lithium. 
     
     
       14. The method of  claim 12 , wherein the lithium aluminum alloy comprises properties to meet a requirement of 100,000 pounds per square inch (“psi”) tensile strength and 80,000 psi yield strength. 
     
     
       15. The method of  claim 1 , wherein prior to detecting a bleed out or a run out, the method comprises extruding a product of the molten metal comprising lithium-aluminum alloy. 
     
     
       16. The method of  claim 15 , wherein the product is a component for an aircraft or an automobile.